Bimodality is sometimes used to test whether a sample (say of visually indistinguishable cells) is made up of two types.
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André NicolasOct 31 '12 at 19:23

Sample modes are a tricky thing for continuous data, so if such a test exists it would almost certainly be for categorical or discrete data. I'm not aware of any, though.
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Jonathan ChristensenNov 1 '12 at 4:01